#include<stdio.h>

int main()
{
	int num = 0, i = 0 ;
	printf("input a number:\n");
	scanf("%d",&num);
	
	/*for(i = 2;i * i <= num ; i++){
		if(num % i == 0)
			break;
	}*/


	i = 2;
	while(i * i <= num){
		if(num % i == 0)
			break;
		i ++;
	}	


	if(i * i <= num)
		printf("the number is not prime number !!\n");
	else 
		printf("the number is prime number!!\n");


	return 0;
}
